1. Field of Invention
This invention relates generally to the electrical stimulation devices for effecting faradic, electromagnetic or other forms of electrical stimulation, and more particularly, to a multi-functional system for this purpose capable of selectively yielding electrical stimulation signals for a broad spectrum of different biological and bio-medical applications as well as for other applications, such as electrophoresis.
2. Status of Prior Art
Electrical stimulation (ES) is widely used in biological and bio-medical research as well as in diagnostics and in clinical treatment. In faradic stimulation an intermittent or a continuous direct or or alternating current or voltage is produced, whereas in electromagnetic stimulation, a current passing through a coil produces an electromagnetic field whose pattern depends on the wave form of the current.
Electrical stimulation is employed to effect nerve regeneration, in neuromuscular research, in medical diagnosis and treatment, and in pulsed voltage electrophoresis. Such stimulation is also used in bone healing and in wound healing, in pain relief by means of transcutaneous electrical nerve stimulation (TENS). The use of ES to effect nerve regeneration is disclosed in the Zanakis et al. U.S. Pat. No. 4,774,967 as well as in the Borgens U.S. Pat. No. 4,919,140.
Researchers in the biological and medical sciences, physiotherapists, and clinicians who make use of ES require electrical stimulators of a type suitable for the activities in which they are engaged. Thus neurological investigators who seek to non-invasively stimulate deep nerves make use of commercially available magnetic stimulators which produce a high-intensity magnetic field pulse for this purpose.
Also commercially available are constant current stimulators for direct cortical stimulation as well as electrical stimulators for nerve and muscle stimulation procedures which generate single or double pulses, or trains of such pulses. And commercially available are wave generators capable of selectively generating sine and square wave pulses suitable for other types of electrical stimulation.
But what is not available to researchers and others who make use of electrical stimulation is a multi-functional system capable of yielding an electrical stimulation signal that is appropriate for whatever biological or biomedical application is the concern of the user of the system.
Let us assume, by way of example, that a researcher is engaged in a neurological research program in the course of which it becomes necessary to conduct tests on the effects of many different types of electrical stimuli on a certain set of nerves. The researcher would then have to assemble from different commercial sources the several electrical stimulators of different types called for by this program. This burdensome requirement adds substantially to the cost of conducting this research and to its space demands.
While the invention will be described herein as a system for producing electrical stimulating signals, the signals produced thereby can also be used for electroporation, electrophoresis (preferably pulsed voltage electrophoresis) and iontophoresis as well as for electrochemical applications as in the treatment of cancer in which a current is passed through the tissue being treated. The signals can also be used to transdermal drug delivery.